Coffee is commonly consumed by many surgeons due to its suspected effect on both performance and mental alertness. Our objectives in this study were to evaluate the effect of different doses of caffeine on performance of laparoscopic skills in a virtual setting.

Methods

We recruited 28 medical students who fulfilled the inclusion criteria (no prior laparoscopic experience, virtual or otherwise). They performed laparoscopic tasks under three conditions: decaffeinated, 100mg caffeine and 200mg caffeine taken as coffee one hour before the task. Candidates were crossed over to the other caffeine doses on different days.

The tasks performed were: Hand-eye Coordination (task 3), Two-handed Manoeuvres (task 6), Cutting task (Task 7) and Electrocautery task (Task 8) using the Lap Mentor™ (Simbionix®). All the candidates performed 3 repetitions of each task. Performance was compared by measuring completion time, accuracy, number of movements and total path length. All data was collected in Excel and analysed using SPSS version 21. We used a tailed T-test and p-values <0.05 were considered statistically significant at 5% level.

Results

Seventeen out of twenty eight candidates completed the study. There were 8 males and 9 females with a mean age of 22.4 years. Table 1 shows the difference by the candidates under the 3 different doses.

Table 1

Task

Total Completion Time/s

Accuracy/%

Total Number of Hand Movements

Total Path Length/cm

Decaf

100mg

200mg

Decaf

100mg

200mg

Decaf

100mg

200mg

Decaf

100mg

200mg

Task 3

687

755

713

92.59

95.19

94.28

779

845

842

3819

4000

4121

Task 6

1877

1922

1801

92.59

94.12

94.34

2671

2722

2652

9237

8743

8772

Task 7

1576

2024

1810

99.49

99.07

99.28

2614

3335

3026

5693

7018

6349

Task 8

3155

3428

3337

96.45

97.01

97.10

2513

2824

2776

6556

6841

7025

The decaffeinated group had a faster completion time than 100mg in task 3(p=0.193), 6(p=0.371), 7(p=0.004) and 8(p=0.049) and a faster completion time than 200mg in task 3(p=0.527), 7(p=0.071) and 8(p=0.188) but not task 6(p=0.525). The decaffeinated group only showed a higher accuracy score compared to 100mg and 200mg of caffeine in task 7 (p=0.24 and 0.604 respectively) but showed a lower accuracy score compared to 100mg and 200mg caffeine in task 3(p=0.062 and 0.290 respectively), 6(p=0.469 and 0.466) and 8(p=0.477 and 0.932 respectively). The decaffeinated group had fewer hand movements than 100mg and 200mg caffeine in task 3(p=0.218 and 0.230 respectively), 7(p=0.007 and 0.122 respectively) and 8(p=0.154 and 0.055 respectively) and 100mg in task 6(p=0.840). The decaffeinated group had a shorter path length than 100mg and 200mg caffeine in task 3(p=0.035 and 0.210 respectively), 7(p=0.039 and 0.154 respectively) and 8(p=0.526 and 0.138 respectively) but not in task 6(p=0.393 and 0.344 respectively).

Conclusions

Caffeine had little effect on laparoscopic performance of basic tasks (task 3, 6), but had more negative effects on advanced tasks (task 7, 8) in a simulated setting though the difference was not dose dependent. Further studies may aim to evaluate whether this has any significance on clinical practice.